JPH0810330B2 - Photosensitive resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a water-developable photosensitive resin composition capable of being hot melt molded.

(Prior Art and Problems Thereof) A water-developable photosensitive resin composition for forming a printing plate, a relief plate or a resist pattern is known. Generally, these photosensitive resin compositions are obtained from a mixture of water-soluble or water-dispersible polyvinyl alcohol, a polymerizable monomer and a photopolymerization initiator.

This composition is used by irradiating light to form a latent image by being polymerized, and a portion not exposed to light is washed off with water or the like to form a development relief.

This photosensitive resin composition is usually obtained by dissolving polyvinyl alcohol in water, then adding a monomer, coating the substrate, and evaporating the water.

This method requires a drying step for evaporation of water, and requires a large amount of equipment, a place and time. Further, many of the monomer components added to the photosensitive resin composition have a low molecular weight and a low boiling point, and the monomer is scattered during drying, which causes a problem of environmental pollution.

Further, when a polyvinyl alcohol having a high degree of saponification is used, the developed relief has the drawbacks of being hard and cracking, so it is necessary to lower the hardness. Low hardness can be imparted by lowering the saponification degree of the vinyl ester unit of polyvinyl alcohol, but if the saponification degree of the vinyl ester unit is lowered, the water solubility is poor and water development becomes difficult.

On the other hand, from the viewpoint of printing, low hardness is one of the performances required for excellent printing performance, which cannot be neglected. Also, the elasticity of the relief is one of the performances required for excellent printing performance.

Therefore, it is necessary to provide low hardness, rubber elasticity, and water solubility.

(Object of the Invention) The present invention is a photosensitive resin composition that can be melt-molded without requiring a drying step, has high compatibility and water solubility, and has appropriate hardness and rubber elasticity when cured. Provide things.

(Structure of the invention) That is, the present invention is (a) a vinyl ester obtained by saponifying a copolymer of 90 to 99.9 mol% of vinyl ester and 0.1 to 10 mol% of an ionic hydrophilic group-containing polymerizable monomer. The degree of saponification of the unit is 50 to 70 mol%, the temperature at which the melt starts to flow 60 to 130 ° C
A polyvinyl alcohol-based copolymer having: (b) Formula: [In the formula (I), However, R ₁ , R ₃ and R ₄ are the same or different and each is a hydrogen atom or a methyl group, R ₂ is an alkylene group having 1 to 5 carbon atoms having a hydroxyl group, and R ₅ is 1 to 1 carbon atoms having a hydroxyl group.
An alkyl group of 5, n is an integer of 4 to 23, m is 0 or 1,
And p represent the integer of 1-5. ] And a polymerizable monomer having at least two free hydroxyl groups, and (c) a photopolymerization initiator, and a melt-formable water-developable photosensitive resin composition.

Component (a) In obtaining the polyvinyl alcohol-based copolymer (a) used in the photosensitive composition of the present invention, the vinyl ester may be vinyl formate, vinyl acetate, vinyl propionate,
Although vinyl benzoate and the like can be used, vinyl acetate is preferably used.

The ionic hydrophilic group-containing polymerizable monomer is an ethylenically unsaturated group copolymerizable with the vinyl ester and an ionic hydrophilic group, for example, a carboxyl group or a salt thereof, a sulfonic acid group or a salt thereof, a phosphoric acid group or a salt thereof. And the like, and a compound containing an ionic group such as an amino group or a cationic group such as an ammonium group. Examples of such a monomer include (meth) acrylic acid or a salt thereof, itaconic acid or a salt thereof, maleic acid or a salt thereof, fumaric acid or a salt thereof, maleic anhydride, 2-acrylamide-
2-methylpropanesulfonic acid or a salt thereof, (meth)
Allylsulfonic acid or a salt thereof, (meth) acrylamidopropyltrimethylammonium chloride and the like can be mentioned. The ionic hydrophilic group-containing polymerizable monomer greatly affects the water solubility of the polyvinyl alcohol-based copolymer and the compatibility between the polymer and the polymerizable monomer. Among the above-mentioned, preferable ionic hydrophilic group-containing polymerizable monomers are (meth) acrylic acid, itaconic acid, maleic anhydride, and 2
-Acrylamido-2-methylpropanesulfonic acid,
(Meth) acrylic sulfonic acid may be mentioned.

In the copolymer, the content of the ionic hydrophilic group-containing polymerizable monomer is 0 from the balance of meltability and water solubility.
1-10 mol% is preferred. More preferably, 0.2 to 7 mol% of the ionic hydrophilic group-containing polymerizable monomer is used. When the content of the above monomer is lower than 0.1 mol%, the meltability of the obtained composition is poor, and when it exceeds 10 mol%, the solid retention of the composition is poor and the composition cannot be used.

The polyvinyl alcohol-based copolymer (a) of the present invention is
It is obtained by saponifying the above copolymer by a usual method.
The performance required for the polyvinyl alcohol-based copolymer of the present invention is that the melt viscosity of the obtained composition is applicable, that the compatibility with the polymerizable monomer is good,
Water-soluble, dimensional stability of the resulting photosensitive resin plate (heat retention creep of solid retention of the composition) and the like are mentioned, but in order to satisfy these required performance, Thermal melting flow starting temperature of polymer is 60 ℃ -130 ℃
It is necessary that the saponification degree is 50 to 70 mol%,
Regarding the degree of polymerization, it is desirable that the average degree of polymerization is 1000 or less, preferably 700 or less, more preferably 500 or less and 100 or more. That is, those having an average degree of polymerization of more than 1000 are unsuitable because the melt viscosity is too high, while those of less than 100 have poor retention of the polymerizable monomer and are difficult to use, and the degree of saponification is radical Depending on the content of the polymerizable monomer unit, those having a content of 50 mol% to 70 mol% have excellent compatibility with the polymerizable monomer and are easy to use. It is unsuitable because it is too high. If it is less than 50 mol%, the dimensional stability of the resin plate tends to be poor, and it cannot be used.

The melt flow initiation temperature of the polyvinyl alcohol-based copolymer of the present invention was measured by using a polyvinyl alcohol-based copolymer having a water content of 3% by weight with a flow tester equipped with a nozzle having a diameter of 1 mm and a length of 1 mm and a load of 50 kg. Below, the flow starting temperature is shown when the temperature is raised at 6 ° C./min and the melt is discharged.
In addition, the term "water-soluble" as used in the present invention means 1% by weight at 25 ° C
When the polyvinyl alcohol-based copolymer is dissolved in water so as to have a concentration, it means that it completely dissolves or disperses. The average degree of polymerization () is calculated from the viscosity formula by measuring the intrinsic viscosity [η] of the polyvinyl alcohol-based copolymer at 30 ° C in water.

Component (b) The polymerizable monomer used in the present invention is a compound represented by the above formula (I) and needs to have at least two hydroxyl groups. Therefore, even if the formula (I) is satisfied, those having 1 or 0 hydroxyl groups are omitted. Examples of this compound include: Further, it may be a (meth) acrylic acid ester derivative in which the terminal hydroxyl group of the above compound is esterified with acrylic acid or methacrylic acid.

Other general monomer species may be added to the above special monomer.

Specific examples of other monomers having a polymerizable double bond in the molecule include methyl acrylate, ethyl acrylate,
n-propyl acrylate, β-hydroxyethyl acrylate, β-hydroxypropyl acrylate, polyethylene glycol monoacrylate, polypropylene glycol monoacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, methoxy polyethylene glycol monoacrylate, ethoxy polyethylene glycol monoacrylate, Glycerol diacrylate, pentaerythritol diacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate,
Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl methacrylate, polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, methoxypolyethylene glycol monomethacrylate, ethoxy Polyethylene glycol monomethacrylate, glycerol dimethacrylate, pentaerythritol dimethacrylate, trimethylolpropane trimethacrylate, etramethylolmethane tetramethacrylate, acrylamide, N-methylolacrylamide, n-butoxymethylacrylamide, isobutoxyacryl Amide, n-t-butylacrylamide, methylenebis (acrylamide), ethylenebis (acrylamide), propylenebis (acrylamide), methacrylamide, N-methylolmethacrylamide, n-butoxymethylmethacrylamide, isobutoxymethacrylamide, n-t -Butyl methacrylamide, methylene bis (meth acrylamide), ethylene bis (meth acrylamide), propylene bis (meth acrylamide) or a mixture thereof can be mentioned.

The specific selection of the polymerizable monomer may be performed in consideration of the compatibility depending on the type of the polymer used. If necessary, in order to assist the compatibility between the two, an appropriate solvent such as water or a high boiling point alcohol (for example, ethylene glycol, diethylene glycol, propylene glycol, triethylene glycol, butanediol, trimethylolpropane, tetramethylolethane, glycerol). , Diglycerol) may be added.

Component (c) There is no particular limitation on the photopolymerization initiator (c), but an aromatic ketone is usually used. A compound having an aromatic ring and a carbonyl group in the molecule is used as the aromatic ketone, and specific examples thereof include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, α-methylbenzoin, 2-
Methyl anthraquinone, 9-fluorenone, benzyl,
Examples thereof include benzylmethyl ketal, acetophenone, 2,2-dimethoxy-2-phenylacetophenone, benzophenone, phenyl-2-thienyl ketone, p-dimethylaminobenzophenone and p-p'-tetramethyldiaminobenzophenone. These compounds optionally include cyano group, nitro group, methoxy group, sulfonic acid group,
Substituents such as phosphinic acid or its salts or esters may be present. Examples of such are 2,6-dimethoxybenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, ethyl ester of 2,4,6-trimethylbenzoyl-phenylphosphinic acid,
Examples include sodium salt of 2,4,6-trimethylbenzoyl-phenylphosphinic acid.

Others The mixing ratio of the above-mentioned essential components (a), (b) and (c) is usually 0.01 to 10 parts by weight of the photopolymerization initiator (c) and 100 parts by weight of the polymerizable monomer (b) and the polyvinyl alcohol-based copolymer. The amount of the polymer (a) is 50 to 300 parts by weight, preferably 0.02 to 5 parts by weight of (c) and 60 to 250 parts by weight of (a).

In addition to the above essential components, a polymerization inhibitor (for example, 2,6-di-t-butyl-p-cresol, hydroquinone, p-methoxyphenol), a dye (for example, rose bengal, eosin, methylene blue, malachite green), etc., if necessary. May be blended.

Since the photosensitive resin composition of the present invention uses the specific polyvinyl alcohol copolymer (a), it can be processed by hot melt molding. The hot melt molding is usually performed in an extruder.
According to this method, a large drying step is not required,
The process is shortened, and the production cost is significantly reduced. A small amount of water may be used as a plasticizer in the hot melt molding, but the amount used is significantly different from the conventional amount used. The compositions of the present invention can be processed by conventional methods which do not rely on hot melt molding.

A resin plate material is obtained by extrusion-molding the obtained photopolymerizable resin composition on an appropriate support. The support is usually a metal (eg aluminium, zinc, iron),
Plastic (eg polyethylene terephthalate,
Polystyrene, polymethylmethacrylate, nylon,
Cellulose acetate, polyethylene, polypropylene, polycarbonate, polyacrylonitrile, polyvinyl chloride), glass, etc. are used. If necessary, the surface of these supports may be pretreated by etching, electrolytic oxidation, corona discharge, or the like, or a thin layer such as an adhesive layer or an antihalation layer may be provided.

To form an image using the above resin plate material,
The conventional method itself may be adopted. For example, an image film (negative film or positive film) is formed on the surface of the resin plate material through an appropriate film or coating layer if necessary.
And then expose. After the exposure, an image can be formed by removing the unexposed portion with an appropriate developing solution, specifically, water.

At the time of exposure, various actinic ray sources can be used, and examples thereof include a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a xenon lamp, a metal halide lamp, and an ultraviolet fluorescent lamp. Besides, a tungsten lamp, a white fluorescent lamp, a visible light laser, or the like may be used.

(Effect of the Invention) According to the present invention, a photosensitive resin composition that can be hot melt-molded using a specific modified polyvinyl alcohol is obtained.
By using this composition, a drying step is not required, a large-scale apparatus for drying is not required, and the number of steps can be reduced. In addition, environmental pollution due to evaporation of low boiling point monomers generated in the drying step can be prevented. The photosensitive resin composition of the present invention can be developed with water.

Further, in the present invention, a special polymerizable monomer species is used to impart high water solubility to the photosensitive resin composition,
It imparts high rubber elasticity to the cured film obtained by exposure.

The composition of the present invention can be used in various image-forming materials such as resists.

(Example) Hereinafter, the present invention will be described in more detail with reference to examples. However, "part" means "part by weight".

Reference Example 1 Vinyl acetate 2150 parts Methanol 1950 parts, itaconic acid 5 g and 2,2'-azobisisobutyronitrile 7 in a reaction vessel equipped with a stirrer, thermometer, dropping funnel and reflux condenser.
After 5 parts were charged and the system was replaced with nitrogen, the internal temperature was raised to 60 ° C. and the temperature was raised to initiate polymerization. Further, during a polymerization time of 5 hours, 305 parts of a methanol solution containing 105 g of itaconic acid was dropped so that the monomer ratio of itaconic acid and vinyl acetate in the polymerization system would be constant according to the measured value of the solid content concentration of the weight system. did. The solid content concentration in the system when the polymerization was stopped was 31%. After heating while introducing methanol vapor to drive off unreacted vinyl acetate, a 65% methanol solution of the copolymer was obtained. The magnetic resonance (NMR) analysis confirmed that the copolymer contained 5 mol% of itaconic acid units and 95 mol% of vinyl acetate units. 100 parts of a methanol solution of this copolymer was brought to 40 ° C., 23 parts by volume of a 2N sodium hydroxide methanol solution was added with stirring, and they were mixed well and saponified. After 30 minutes, the obtained white gel was crushed with a crusher, sufficiently washed with methyl acetate / methanol = 7/3 (weight ratio), and then dried to obtain a polyvinyl alcohol copolymer a. The saponification degree of the vinyl ester unit of the copolymer was found to be 57 mol% by NMR analysis. The degree of polymerization determined by measuring the intrinsic viscosity in an aqueous solution was 380. Furthermore, the temperature at which the polyvinyl alcohol-based copolymer a started to melt and flow was measured by a flow tester to find that it was 98 ° C.
Met.

Reference Example 2 In a reactor similar to that of Reference Example 1, 180 parts of vinyl acetate, 3500 parts of methanol, and 1 part of sodium salt of 2-acrylamido-2-methylpropanesulfonic acid were charged, and the inside temperature was changed to 60 after nitrogen substitution with stirring. The temperature was raised to ° C. 2,2'- in the reactor
Polymerization was initiated by adding 24 parts of azobisisobutyronitrile together with 150 parts of methanol. During a polymerization time of 3 hours, 35 parts of a methanol solution containing 11 parts of 2-acrylamido-2-methylpropanesulfonic acid sodium salt was continuously added dropwise to the system depending on the solid content concentration of the polymerization system. The solid content concentration in the system when the polymerization was stopped was 23.3%. After removing unreacted vinyl acetate by introducing methanol vapor,
A 65% methanol solution of the copolymer was obtained. This copolymer
NMR analysis revealed that the content of 2-acrylamido-2-methylpropanesulfonic acid sodium salt unit was 0.35 mol%.

To 100 parts of the copolymer methanol solution, 11 parts of a 2N sodium hydroxide methanol solution was added and saponified at 40 ° C. for 30 minutes. The obtained white gel was crushed with a crusher, washed with a mixed solution of methyl acetate / methanol = 8/2 (weight ratio) and then dried.

The obtained polyvinyl alcohol-based copolymer b was analyzed in the same manner as in Reference Example 1. As a result, the degree of saponification of the vinyl ester unit was 61 mol%, the degree of polymerization was 350, and the hot melt flow starting temperature was 101 ° C.
Met.

Reference example 3 xylene 370g and structural formula in 2l Kolben equipped with stirrer, condenser and temperature controller The main component is a bifunctional epoxy compound (commercially available from Kyoeisha Yushi Kagaku Kogyo Co., Ltd. as Epolite 400E), 526 g, methacrylic acid 86 g, pure water 18 g and tetrabutylammonium chloride 1 g are charged, the temperature is raised with stirring, and the reflux state is maintained. Hold for 30 minutes. Then, the temperature was cooled to room temperature.

The analysis results of the obtained photopolymerizable vinyl monomer are NM
From R and IR, it was confirmed to be the polymerizable monomer (III). Its acid value was 0.56 and its viscosity was 200 cps.

Reference Example 4 The same procedure as in Reference Example 3 was carried out except that 410 g of xylene, 526 g of the bifunctional epoxy compound listed in Reference Example 3, 72 g of acrylic acid, 18 g of pure water and 1 g of tetrabutylammonium chloride were charged, and the polymerizable monomer ( II) was obtained. The acid value was 0.59 and the viscosity was 170 cps.

Reference Example 5 The same procedure as in Reference Example 3 was carried out except that 330 g of xylene, 526 g of the bifunctional epoxy compound listed in Reference Example 3, 144 g of acrylic acid, and 1 g of tetrabutylammonium chloride were charged to obtain the polymerizable monomer (IV). .

Reference example 6 Structural formula in a 2 l Kolben equipped with a stirrer, condenser and temperature controller Is a main component polyethylene glycol monomethacrylate compound (commercially available from NOF Corporation as Bremmer PE350) 964g, glycidol (manufactured by Daicel Chemical Industries, Ltd.) 148g and dimethylbenzylamine 11g are charged, stirred while blowing air, 120 ° C The temperature was raised to ~ 140 ° C and maintained for 1 hour. Then, the temperature was cooled to room temperature.

The analysis results of the obtained photopolymerizable vinyl monomer are NM
From R and IR, it was confirmed to be the above-mentioned polymerizable monomer (VII). Its acid value was 0.10 and its viscosity was 150 cps.

Reference Example 7 Polyethylene glycol monoacrylate compound 936 g,
The same procedure as in Reference Example 6 was carried out except that 148 g of glycidol and 11 g of dimethylbenzylamine were charged to obtain the polymerizable monomer (VI). The acid value was 0.12 and the viscosity was 130 cps.

Example 1 100 parts by weight of polyvinyl alcohol copolymer a (saponification degree of vinyl ester unit: 57 mol%, degree of polymerization: 380), 15 parts by weight of ethylene glycol, and 10 parts by weight of pure water were placed in a kneader and the temperature was 80 to 85 ° C. And mixed for 30 minutes.

Polymerizable monomer (III) 100 prepared by synthesizing 0.1 part of p-methoxyphenol, 0.4 part of 2,6-di-t-butyl-p-cresol and 3 parts of 2,2'-dimethoxy-2-phenylacetophenone in Reference Example 3 above. Dissolved in part. The obtained solution was added to the above mixture and kneaded at 80 ° C for 30 minutes, and the mixture was continuously fed at 80 ° C using a twin-screw extruder, mixed, defoamed, and coated with an antihalation agent. 0.5 on a 0.2 mm treated iron plate
Discharged to a thickness of mm. Then, the cover film was laminated.

Negative film for test (150 lines 3%, 5%, 10%, 20% halftone dot, diameter 1
00μ, 200μ, independent points, width 40μ, and 60μ thin line part) were vacuum-contacted, and a 3Kw high-pressure mercury lamp was irradiated from a distance of 70cm. The irradiation time was 4 seconds for pre-exposure and 26 seconds for main exposure. The exposed plate material was developed by spraying neutral water at 40 ° C. for 1 minute at a pressure of 4 kg / cm ² from a spray developing device.
The unexposed portion, that is, the uncured portion was dissolved in water to obtain a relief. When the relief plate thus obtained was dried at 100 ° C. for 2 minutes, 3% halftone dot, diameter 100
No loss of μ, independent point, and 40 μ width thin line was observed.

When this plate material was printed using a Bandak Cook proof press (manufactured by Bandak Cook), the solid density was 1.20.
(Measured with a Macbeth reflection densitometer), and a paper surface with a good stickiness in the solid portion was obtained.

In addition, the discharge of the twin-screw extruder used for producing this plate material was used as a photosensitive resin plate having a thickness of 2 mm by a flexo press using a spacer having a thickness of 2 mm. The plate was exposed with a 3 Kw high pressure mercury lamp for 5 minutes. Hardness and elasticity were measured by cutting it into 2 cm squares and stacking them to a thickness of 12 mm. The hardness was 50 ° C (measured at 20 ° C) and the impact resilience value was 27% (JI
SK-6301 method, measured at 20 ° C.).

Examples 2 to 6 and Comparative Examples 1 to 3 By combining the polyvinyl alcohol copolymer and the polymerizable monomer shown in Table 1, photosensitive resin plate materials were obtained in the same manner as in Example 1 and the same experiment was conducted. Table 1 shows the plate making conditions and the experimental results.

For comparison, 80 parts of the following three types of polymerization biomonomers and the polyvinyl alcohol copolymer 100 obtained in the above reference example were used.
Similar experiments were conducted in combination with the parts. The results are shown in Table 1.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area C08F 220/58 MNG 299/02 MRS G03F 7/027 502

Claims (5)

[Claims] 1. A saponification degree obtained by saponifying a vinyl ester unit of a copolymer of (a) 90 to 99.9 mol% of a vinyl ester and 0.1 to 10 mol% of an ionic hydrophilic group-containing polymerizable monomer.
A water-soluble or water-dispersible polyvinyl alcohol-based copolymer having 50 to 70 mol% and a hot melt flow starting temperature of 60 to 130 ° C. (b) Formula: [In the formula (I), However, R ₁ , R ₃ and R ₄ are the same or different and each is a hydrogen atom or a methyl group, and R ₂ is a hydroxyl group-containing carbon atom 1
~ 5 alkylene group, R ₅ has a hydroxyl group having 1 to 5 carbon atoms
Of the above, n is an integer of 4 to 23, m is 0 or 1, and p is an integer of 1 to 5. ] And a hot melt moldable water-developable photosensitive resin composition containing a polymerizable monomer having at least two free hydroxyl groups, and (c) a photopolymerization initiator. 2. The composition according to claim 1, wherein the vinyl ester is vinyl acetate. 3. The composition according to claim 1, wherein the polymerizable monomer containing an ionic hydrophilic group is sodium 2-acrylamido-2-methylpropanesulfonate. 4. The saponification degree of the vinyl ester unit of polyvinyl alcohol is 55 to 68 mol%.
The composition according to the item. 5. A mixing ratio of the components (a), (b) and (c) is 0.01 to 10 parts by weight relative to 100 parts by weight of (b).
The composition according to claim 1, wherein (a) is 50 to 300 parts by weight.